1. Field of the Invention
The invention relates to a fuel cell diagnostic apparatus and diagnostic method. More particularly, the invention relates to an improvement in technology for diagnosing whether there is an abnormality in a fuel cell.
2. Description of the Related Art
A fuel cell (such as a polymer electrolyte fuel cell) is typically made by stacking together a plurality of cells (power generating cells) each having an electrolyte sandwiched between separators. Conventionally, in one such fuel cell formed of these cell stack bodies, a cell monitor is provided to measure the voltage of the cell (i.e., the cell voltage) so that the power generating status such as the fluctuation in cell voltage while power is being generated in the fuel cell can be monitored. More specifically, technology is described that enables the current distribution while power is being generated in the fuel cell to be detected by a magnetic sensor provided in the cell, for example (see Japanese Patent Application Publication No. JP-A-2005-123162, for example).
However, even if there is a measure to detect the current distribution while power is being generated in the fuel cell, as described above, there is no measure to diagnose the distribution of water in an electrolyte membrane when power is not being generated in the fuel cell.